First Online: 23 May 2015Received: 22 September 2014Accepted: 14 May 2015

Abstract

IntroductionT cells play an important role in the pathogenesis of systemic lupus erythematosus SLE. Clonal expansion of T cells correlating with disease activity has been observed in peripheral blood PB of SLE subjects. Recently, next-generation sequencing NGS of the T cell receptor TCR β loci has emerged as a sensitive way to measure the T cell repertoire. In this study, we utilized NGS to assess whether changes in T cell repertoire diversity in PB of SLE patients correlate with or predict changes in disease activity.

MethodsTotal RNA was isolated from the PB of 11 SLE patients. Each subject had three samples, collected at periods of clinical quiescence and at a flare. Twelve age-matched healthy controls HC were used for reference. NGS was used to profile the complementarity-determining region 3 CDR3 of the rearranged TCR β loci.

ResultsRelative to the HC, SLE patients at quiescence demonstrated a 2.2-fold reduction in repertoire diversity in a given PB volume P <0.0002, a more uneven distribution of the repertoire Gini coefficient, HC vs SLE, P = 0.015, and a trend toward increased percentage of expanded clones in the repertoire clone size >1.0 %, HC vs SLE, P = 0.078. No significant correlation between the overall repertoire diversity and clinical disease activity was observed for most SLE patients with only two of eleven SLE patients showing a decreasing trend in repertoire diversity approaching the flare time point. We did not observe any overlap of CDR3 amino acid sequences or a preferential Vβ or Jβ gene usage among the top 100 expanded clones from all SLE patients. In both HC and SLE, the majority of the expanded clones were remarkably stable over time HC = 5.5 ±0.5 months, SLE = 7.2 ±2.4 months.

ConclusionsA significant decrease in T cell repertoire diversity was observed in PB of SLE patients compared to HC. However, in most SLE patients, repertoire diversity did not change significantly with increases in disease activity to a flare. Thus, without a priori knowledge of disease-specific clones, monitoring TCR repertoire in PB from SLE patients is not likely to be useful to predict changes in disease activity.